Electronic circuit components are mounted on a circuit substrate so as to provide an electronic circuit. For example, electronic circuit components are held by a carrier tape, and the carrier tape is fed by a tape feeder so as to supply the electronic circuit components. The carrier tape has a multiplicity of feed holes arranged in a lengthwise direction thereof, and a multiplicity of component accommodating pockets that are arranged in the lengthwise direction and accommodate respective electronic circuit components and that have a predetermined relative position relative to the feed holes. When the carrier tape is fed by a feeding device of the tape feeder, the respective electronic circuit components accommodated by the component accommodating pockets are sequentially positioned at a component-supply position.
It is desirable that each of the electronic circuit components be accurately positioned at the component-supply position. However, because of, e.g., manufacturing errors and/or assembling errors of the tape feeder, positional errors may occur to the tape feeder so that when an electronic circuit component is taken from a component accommodating pocket, a failure to take the component may occur. Conventionally, various countermeasures have been proposed to solve this problem. For example, the below-identified Patent Document 1 discloses an electronic-circuit-component supplying and taking apparatus that takes, with an image taking device, an image of a feed hole of a carrier tape, subsequently obtains, based on image data representing the taken image, an error of a relative position of the feed hole relative to the image taking device, and corrects, based on the obtained relative-positional error, a component-take position where a suction nozzle takes an electronic circuit component from the carrier tape. Generally, in a carrier tape, a plurality of feed holes and a plurality of component accommodating pockets are accurately formed such that the component accommodating pockets have a predetermined relative position relative to the feed holes. Thus, a component accommodating pocket to be positioned at a component-supply position has a predetermined relative position relative to a feed hole whose image is to be taken by the image taking device, and accordingly a positional error of the feed hole whose image has been taken by the image taking device can be regarded as a positional error of the component accommodating pocket currently positioned at the component-supply position. In many cases, identical feed holes are commonly formed in different sorts of carrier tapes. Since, in those cases, respective images of the identical feed holes are taken and processed, it needs only a less amount of image data to process, or needs only a shorter time to process image data, as compared with the case where images of the component accommodating pockets or the electronic circuit components are taken and processed to obtain relative-positional errors of the component accommodating pockets.    Patent Document 1: Japanese Patent Application Publication No. 2003-347794